Now that it is getting warmer, I am starting to pretty consistently see some behaviour that I had been attributing to the SC check valve not working properly.

Today was a perfect example of this behaviour: warm day (80+), drive home from work on the highway, haul ass as usual (when traffic safely permits), about 25 miles total but last 4 miles or so on secondary roads with stop lights. Car runs well on the highway but when I get into the stop light traffic, performance seems really poor - best way I can describe it is like a bunch of cotton has been stuck up my tailpipe, restricting flow. Car is not as smooth, timbre of exhaust changes to sound rougher, louder, a little strained. Hard to leave from a stop light without bogging down and acceleration sucks big time.

If the car doesn't sit long enough before I drive it again, it still drives poorly and I do mean poorly - the effect I am experiencing is way too pronounced to be normal. If it gets a while to cool down, it drives fine.

Please don't tell me this is normal behaviour for the S2K! Is there any way the SC could be contributing to this behaviour? This effect occurs at all rpm ranges, including lower rpms where there isn't (shouldn't be) any boost.

Car gurus, please shower me with your wisdom!

 

Well, I'm not a guru but I've had the same problem with my non-S/C'd car. Most people attribute those symptoms to the air flow sensor on the throttle body.

I've had mine changed at the dealer and I haven't had any major problems since then.

I've had all of the documented problems below:

1) Lower than usual idle when stuck in traffic (after driving highway speeds for a while).
2) Bogging/bucking/lurching when trying to get up to speed after being stuck in traffic.
3) VTEC seems to kick in and out when staying over 6K rpm.
4) Couldn't get past 7K rpm when WOT. The car was warmed up(after 20 minute highway driving) and felt like I hit the REV Limiter.

Oh yeah, back to your question. The car definately runs slower in the heat. It almost feels like it has lost about 20 horses on some 100+ degree days.

 

[QUOTE]Oriinally posted by joe_s2k:
[B]Well, I'm not a guru but I've had the same problem with my non-S/C'd car. Most
people attribute those symptoms to the air flow sensor on the throttle body.

 

the dealer installed my SC - I did this all through the dealer with the express understanding that the SC would not void any warranties.

Besides, if somebody without the SC has had problems with the air flow sensor, there is no reason the think the SC had anything to do with that problem (if that is the problem I have). People without mods have also had problems with their MAP sensors, so clearly there is some "infant mortality" in some of these sensors.

If I did not have the SC, my car would have been to the dealer weeks ago. It has just not been clear to me whether the SC was the problem or not, but I am starting to believe that it is not the SC, but something else. I have been working closely with Comptech on my problems and they have been very responsive; I have also talked to others with the SC. I think I am finally getting enough information to perhaps eliminate the SC as the issue. That's why I posted my question - to see if others had experienced the same kind of problems.

 

hecash,

yes, i have the latest check valve as you describe. I had a long discussion with Mike B. from comptech yesterday and part of that conversation had to do with the ECU and how it reacts to certain conditions. It seems that for some reason when it is hot, the ECU sees a set of conditions that it thinks is "bad" and retards the timing (or whatever) to make sure things are safe. How or if this is related to the SC is beyond me. The problem I described at the beginning of the thread shows up even at rpms where there isn't any boost, so the check valve shouldn't even be an issue in these circumstances.

I am definitely going to get the dealer to check the car soon.